From c67bf898c9e13d8c5ffaf9515c83f4bbdb34e8e9 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Sun, 1 Aug 2021 20:00:23 -0700 Subject: [PATCH] spi: mediatek: Fix fifo transfer commit 0d5c3954b35eddff0da0436c31e8d721eceb7dc2 upstream. Commit 3a70dd2d0503 ("spi: mediatek: fix fifo rx mode") claims that fifo RX mode was never handled, and adds the presumably missing code to the FIFO transfer function. However, the claim that receive data was not handled is incorrect. It was handled as part of interrupt handling after the transfer was complete. The code added with the above mentioned commit reads data from the receive FIFO before the transfer is started, which is wrong. This results in an actual transfer error on a Hayato Chromebook. Remove the code trying to handle receive data before the transfer is started to fix the problem. Fixes: 3a70dd2d0503 ("spi: mediatek: fix fifo rx mode") Cc: Peter Hess Cc: Frank Wunderlich Cc: Tzung-Bi Shih Cc: Hsin-Yi Wang Signed-off-by: Guenter Roeck Tested-by: Hsin-Yi Wang Tested-by: Tzung-Bi Shih Link: https://lore.kernel.org/r/20210802030023.1748777-1-linux@roeck-us.net Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman --- drivers/spi/spi-mt65xx.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c index 419aecb94274..dd0bf25d4550 100644 --- a/drivers/spi/spi-mt65xx.c +++ b/drivers/spi/spi-mt65xx.c @@ -337,24 +337,15 @@ static int mtk_spi_fifo_transfer(struct spi_master *master, mtk_spi_prepare_transfer(master, xfer); mtk_spi_setup_packet(master); - cnt = xfer->len / 4; - if (xfer->tx_buf) + if (xfer->tx_buf) { + cnt = xfer->len / 4; iowrite32_rep(mdata->base + SPI_TX_DATA_REG, xfer->tx_buf, cnt); - - if (xfer->rx_buf) - ioread32_rep(mdata->base + SPI_RX_DATA_REG, xfer->rx_buf, cnt); - - remainder = xfer->len % 4; - if (remainder > 0) { - reg_val = 0; - if (xfer->tx_buf) { + remainder = xfer->len % 4; + if (remainder > 0) { + reg_val = 0; memcpy(®_val, xfer->tx_buf + (cnt * 4), remainder); writel(reg_val, mdata->base + SPI_TX_DATA_REG); } - if (xfer->rx_buf) { - reg_val = readl(mdata->base + SPI_RX_DATA_REG); - memcpy(xfer->rx_buf + (cnt * 4), ®_val, remainder); - } } mtk_spi_enable_transfer(master); -- 2.20.1